How significant is the "two billion records" figure? According to the article, the affected smart-home provider mereley "claims to have more than a million users around the world". So presumably this database contains a lot of redundant information?
each user has many records.... from the numbers, I'm guessing around 2000 each (probably light-on... light-off... light-on... light-off).
Most likely not very significant, they probably got the 2 billion records as a upper bound, considering the amount of junk data they likely have in the db, I think its just an overblown news story.